Samuel l



(No M'odeLY I I S. L. BEAN. ROLLER GRINDING MILL.

Patented June 6, 1882 Lilhpgraphar. W ashingmn, D. c.

UNITED STATES,

PATENT Qrrreat SAMUEL L. BEAN, OF WASHINGTON, DISTRICT OI COLUMBIA.

ROLLER GRINDING-MILL.

SPECIFICATION forming part of Letters Patent 'No. 258,877, dated June 6, 1882.

Application filed July 13, 1881. (No model.)

To all whom it may concern Be it known that I, SAMUEL L. BEAN, a citizen of the United States, residing at Washington, District of Columbia, have invented Certain new and useful Improvementsin Roller Grinding-Mills; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being bad to the accompanying drawings, and to the letters or figures of reference marked thereon, which form a part of this specification.

Heretofore it has been customary to subject the chop in its transit from one set of grinding-rollers to the next succeeding set to a screening operationby passing it over a reciprocatin g screen or through a rotating bolt, or through a stationary concave screen co-operating with fan-heaters. In every case'the chop is subjected to a great deal of attrition comparatively, which tends to separate fine yellow flakes from the coarser particles and mix them with the flour and middlings.

The object of my invention is to subject the chop to as little attrition as possible in separating the flour and middlings from it in its passage, from one pair of grinding-rollers to the next pair, and thus preventthe detachment of yellow dust from the bran and its admixture with the flour and middlin gs as far as practicable.

To this end my invention consists mainly in the use of one or more rotating cylindrical screens, arranged under a pair of grindingrollers, for separating the flour and middlings from the chop, which is to fall onto the exterior surface of such rotating cylindrical screen or screens on its way to the next pair of rollers.

It further consists of the combination, with each rotating cylindrical screen, of a trough for conveying away the separated flour and middlings and a brush for cleaning the meshes of the screen.

In order that my invention may be clearly- Fig. 2 is an axial section through one of the after 'each' grinding, one being used, for in-' stance, underthe first pair of grinding-rollers, two under the second pair, and so on. The thing required is to accommodate the separating capacity of the screen or screens to the amount of flour and middlings produce'd at each grinding.

The screens B are cylindrical and made of sieve-cloth of required mesh. They are hung on shafts or journals and are rotated in any suitable manner in the directions of the arrows. The chop is directed'from the grinding-rollers above by a chute, a,it' necessary, toward the axis of the cylindrical screen and onto the exterior surface thereof, so as to spread over the :screen and permit the flour and middlings to pass through its meshes into the interior of the screen. In consequence of its rotation the screen constantly presents fresh surface to the chop. When more than one rotating cylindrical screen is used nnderasingle pair of grinding-rollers, I prefer to arrange such screens stepwise, as shown, so that the chop may fall from one directly onto the next one, and from the lowermost one directly between the next pair of grindingrollers. The separated flour and middlings are received by a trough, 0, preferably arranged within the rotating cylindrical screen, though it may be suspended beneath the same; This trough may contain a conveyer to carry away the separated flour andmiddlings; .or it may be arranged slantingly and vibrated endwise for discharging such flour and middlings. The rotating cylindrical screensmay also be vibrated endwise, so as to jar them somewhat to aid the separation y In order to clean the meshes of the rotating This division of "separa- ICI cylindrical screens, a brush, D, (one or more,) is applied to each, preferably a rotating brush arranged to brush the exterior side of the screen. Air-currents are also drawn through the chest and through the chop and screens to carry oh" the dust and light flour; but I make no claim to this feature, nor to any other feature of this roller grinding-mill, except the rotating cylindrical screens and the combinations thereof.

In fact, I illustrated my invention as embed ied in a roller grinding-mill of the general type exemplified in United States Letters Patent No. 248,578. The rotating cylindrical screens and brushes may be driven by belt-gearing, cog-gearin g, or friction-gearing of any known construction. I make no claim to the means for rotating these devices, and any person skilled in the art can readily applysuch means for rotating them.

The screen B may be supported and driven as shown in Fig. 2, the head of the screen at one end being keyed to ajourual, I), which passes through a bearing on the chest A, and is provided with a pulley, b, so that the screen may be rotated thereby, the other head of the screen being supported on the end of the bearing onthe opposite side of the chest, so as to turn on said hearing. The slanting trough O is suspended at one end from thejournal b by a link adapted to slide on the journal. The other end of the trough is rigidly attached to a sliding rod, b passing through the bearing on which the screen turns, its outer end being secured to a spring, b fastened to the chest and provided with a pin,b, extending through the side of the chest, so that it may be oper ated upon by a cam-surface, 0, formed on the head at this end of the screen. Thus the camsurt'ace will periodically force the pin 1) and the spring b to which it is attached outward, and as soon as the pin 1) escapes from the cam c the spring I) will recoil, and thus the trough U will be reciprocated endwise to discharge the middlings and fine flour through the opposite head of the screens upon a cant-board which directs such middlings and flour to an opening in the chest, as shown in Fig. 2.

Having thusdescribed my invention, what I claim is 1. The combination, substantially as before set forth, of a pair of grinding-rollers and a rotating cylindrical screen, onto the exterior surface of which the chop from the grindingrollers falls.

2. The combination, substantially as before setforth, of a pair of grinding-rollers and a series of rotating cylindrical screens, onto the exterior surface of which the chop from the grinding-rollers falls, arranged stepwise, so that the chop shall pass from the exterior surface of one down upon the next.

3. The combination, substantially as before set forth, of a pair ofgrinding-rollers, a rotating cylindrical screen, cnto the exterior surface of which the chop from the grinding-rollcrs falls, and a brush at a point outside of the flow or current of chop.

4. The combination, substantially as before setforth, of apair ofgrinding-rollers, a rotating cylindrical screen, onto the exterior surface of which the chop from the grinding-rollers falls, and a shaking-trough for conveying away the particles-separated from the chop by the r0- tating screen.

5. The combination, substantially as before set forth, of a pair of grinding-rollers, a rotating cylindrical screen, onto the exterior surface of which the chop from the grinding-rollers falls,and a shaking'trough within the screen.

6. The combination, substantially as before set forth, of a pair of grinding-rollers, a rotatingeylindricalscrceu, onto the exterior surface of which the chop from the grinding-rollers talls, a shaking trough within the screen, and a brush operating on the screen at a point outside of the flow or current of chop.

In testimony whereof I affix my signature in presence of two witnesses.

SAM L. L. BEAN. Witnesses:

O. A. NEALE, C. S. HYER. 

